A thin film transistor liquid crystal display (TFT LCD) includes a TFT array substrate, a color filter over the TFT LCD, and a liquid crystal layer between the TFT array substrate and the color filter. The TFT array substrate can control rotations of liquid crystals in the liquid crystal layer and thus display a picture or shape through the color filter. The TFT array substrate includes electronic components such as thin film transistors, capacitors, connection pads, and connection lines. After the electronic components are formed, an electrically insulating cover is formed to cover the electronic components. Thereafter, the electrical insulating cover is subjected to light exposure through a mask. The light exposure can impart optical qualities to the surface of the electrically insulating cover which are less than optimal, which adversely affects performance and reliability of the TFT array substrate.